The use of raceways to organize and protect communication and electrical power cables in data, voice, and power systems is a commonly observed practice, particularly for those applications where cable damage might otherwise result from inadvertent mechanical force or moisture. The protective features afforded by these systems notwithstanding, successfully installing cables into a raceway system is a challenging task requiring considerable expertise. In the most common scenario in which several cables are to be installed into a single raceway, the combined efforts of at least two technicians are typically required. A first technician positioned at the raceway outlet uses a “fish tape” to pull the cables into the raceway, while a second technician located at the raceway inlet simultaneously guides the cables into the raceway by hand to ensure their uniform entry. The role of the second technician is two-fold. First, by manually guiding the cables into the raceway, the frictional forces encountered by the cables at the raceway inlet are reduced, thereby reducing the pulling effort necessary for cable installation. Second, and perhaps most importantly, manually guiding the conductors into the raceway reduces the chance of tears in the cable insulation or jacketing that expose the cable conductor, commonly referred to as “bare nicks.”
Bare nicks often result in low and high resistance grounds or short circuits in the case of electrical conductors or unacceptable attenuation of optical signals in the case of optical conductors. Even when the technicians are experienced, bare nicks may be unavoidable, occurring approximately once in every one hundred cable pulls. Although the incidence of bare nicks is relatively small, it nonetheless proves to be a costly problem for businesses such as telecommunication providers that install and maintain complex electrical power and communication systems comprising thousands of cables.
One approach that may be used to address the problem of bare nicks is simply to allocate spare cables during the design phase of the electrical power or communication system. If a bare nick is discovered, the defective cable may be taken out of service and replaced with a spare. This approach, however, may increase the installation cost in terms of the cable required and the increased raceway capacity necessary to accommodate it, e.g., where cable lengths are large. Moreover, because the symptoms associated with a bare nick may be sporadic, detecting the problem and identifying its source further increases the costs associated with system maintenance and down time.
A second approach is the use of raceway components having built-in features designed to reduce the occurrence of bare nicks. Conduit connectors that serve as cable entries into raceway systems, for example, are widely available with an insulated throat feature. Typically consisting of a thermoplastic insert glued or pressed into the throat of the connector, the insulated throat is intended to reduce cable abrasion by providing a barrier between the cable and the connector housing as the cable is pulled into the connector. Despite this protective feature, a conduit connector with an insulated throat may be costly than its standard counterpart, further increasing system installation costs.